1. Field of the Invention
The present invention relates generally to circuit breakers and, more particularly, to double-wide circuit breakers that are slidably disposed in a cassette. Specifically, the invention relates to a collapsible handle that is mounted to a pair of circuit breakers that are slidably disposed in a cassette.
2. Description of the Related Art
Numerous types of circuit breakers are known and understood in the relevant art. Among the purposes for which circuit breakers are provided is to interrupt the current flowing through an electrical circuit on command or according to certain criteria. For instance, a given circuit breaker may be configured to interrupt current during one or more specified overcurrent conditions or during other conditions.
Inasmuch as electricity flows through a circuit breaker when the circuit breaker contacts are closed, any given circuit breaker is rated to carry a given maximum current therethrough. Since current requirements can vary from application to application, numerous circuit breakers are provided having different current ratings. While it is desirable to provide different circuit breakers that are suited to different applications having different current requirements, it is undesirable to require that new circuit breakers be designed and manufactured for each new application.
It is thus known to electrically connect a pair of circuit breakers with one another to provide relatively higher xe2x80x9campacityxe2x80x9d or amperage capacity than either of the relatively lower ampacity circuit breakers. In such an arrangement, pairs of the poles of the two circuit breakers are connected in parallel such that a given electrical phase passes through a pair of circuit breaker poles instead of passing through only a single pole.
In such arrangements, the pair of circuit breakers preferably are rigidly connected with one another and may be removably positioned in cassette, with one or more cassettes being mounted in a cabinet. The joined pair of circuit breakers typically is mounted on a pair of extension rails that provide vertical support to the circuit breakers yet permit the circuit breakers to be slidingly and horizontally installed into and removed from the cassette. When the pair of circuit breakers are initially installed into the cassette, the circuit breakers are first placed on the extension rails. The extension rails are then slid rearward into the cassette to enable the quick disconnect members mounted on the conductors at the rear of the circuit breakers to operatively engage a plurality of stabs disposed at the rear of the cassette for electrically connecting the circuit breaker with the line and the load. When it is desired that the circuit breakers be removed from the cassette for maintenance or for other purposes, these circuit breakers are pulled forward away from and are disengaged from the stabs, the circuit breakers resting on the extension rails and sliding thereon during such movement.
While such double-wide circuit breaker configurations have been effective for their intended purposes, such double-wide circuit breaker and cassette configurations have not, however, been without limitation. For instance, depending upon the application, each circuit breaker can be one or two feet wide, or even wider. The combined widths of the joined circuit breakers, as well as any joining blocks or other structures that are interposed between these circuit breakers for the purpose of mechanically fixing them with one another, can easily be two to four feet or more. Such a combined width, along with the weight of the combined circuit breaker assembly which can be on the order of hundreds of pounds, makes the combined circuit breaker assembly extremely difficult for a technician to grasp on alternate ends thereof during installation into and removal from the cassette. The combined width can be such that a technician simply cannot simultaneously grasp the handgrips mounted on each of the extension rails. Such difficulty is particularly exacerbated when it is desired to slide the combined or joined circuit breaker assembly on the extension rails in a forward direction away from the cassette and out of engagement with the stabs.
As is understood in the relevant art, the quick disconnect members mounted on the conductors extending from the rear of the circuit breakers each include a plurality of contact members that are biased into confronting electrical engagement with stabs disposed within the cavity of the cassette. Initial installation of the circuit breakers into the cassette requires a substantial amount of rearward force on the circuit breakers to engage the contact members of the quick disconnect members with the stabs. Likewise, detachment of the contact members from the stabs during removal of the circuit breakers from the cassette requires that a substantial tensile force be applied to the circuit breakers to move the circuit breakers in the forward direction away from the cassette. Application of such a sufficient tensile force can be difficult when the joined circuit breaker assembly is as wide and as heavy as indicated hereinbefore. The need thus exists for a repositioning apparatus for use with draw-out switchgear that can be used to apply a tensile force to a joined circuit breaker assembly to electrically disconnect the joined circuit breaker assembly from a cassette.
It is additionally understood in the relevant art that the joining structure disposed between the circuit breakers functions as a joint between the pair of circuit breakers, with the ends of the circuit breakers opposite the joining structure being supported by the extension rails. The combined weight of the circuit breakers can result in at least nominal sagging at the joining structure, which can interfere with installation and removal of the circuit breakers with respect to the cassette. The need thus exists for a repositioning apparatus that provides support to the circuit breakers and facilitates installation, retention, and removal of the circuit breakers with respect to the cassette.
In view of the foregoing, a handle assembly and an alignment member are mounted on a joining structure that extends between a pair of circuit breakers, the circuit breakers being removably mounted in a cassette. The joining structure may be a single member or may be two or more joining blocks that securely mount the circuit breakers together. The handle assembly includes a housing that is mounted on the joining structure and a handle that is pivotally mounted on the housing. The handle is moveable between an extended position and a retracted position, and the handle is biased to the retracted position by a pair of springs. The alignment member includes a roller pin that is mounted on the joining structure and a roller that is rotatably mounted on the roller pin. The cassette includes a pair of sidewalls, with each sidewall including an extension rail that is extensibly mounted thereon. The cassette further includes a support bar that is interposed between a pair of guide rails that are mounted on the base of the cassette, the support bar being moveable between an inward position and an outward position with respect to the guide rails. The circuit breakers are mountable in the cassette such that each circuit breaker is mounted on one of the extension rails and the alignment member is rotatably disposed against the support bar. When the circuit breakers are initially installed in the cassette, the circuit breakers are slid on the extension rails in a rearward direction to cause the circuit breakers to electrically engage a plurality of stabs that are internally disposed at the rear of the cassette. When it is desired to remove the circuit breakers from the cassette, a tensile force is applied to the handle to disengage the circuit breakers from the stabs and slide the circuit breakers in a forward direction on the extension rails. The alignment member being disposed against the support bar provides support and alignment to the circuit breakers.
An aspect of the present invention is to provide a circuit breaker assembly, the general nature of which can be stated as including a cassette having a pair of side walls and a pair of extension rails, one of the extension rails being extensibly mounted on one of the side walls, the other of the extension rails being extensibly mounted on the other of the side walls, a pair of circuit breakers, one of the circuit breakers being mounted on one of the extension rails, the other of the circuit breakers being mounted on the other of the extension rails, a joining structure extending between the circuit breakers, and a repositioning apparatus structured to facilitate repositioning of the pair of circuit breakers with respect to the cassette.
Another aspect is to provide a repositioning apparatus structured to facilitate repositioning of a pair of circuit breakers with respect to a cassette, the repositioning apparatus being mountable to a joining structure extending between the pair of circuit breakers, the circuit breakers being removably mounted in the cassette, in which the general nature of the repositioning apparatus can be stated as including a handle assembly, the handle assembly including a handle mountable to the joining structure.
Still another aspect of the present invention is to provide an improvement to a circuit breaker assembly of the type including a pair of circuit breakers, a joining structure disposed between the pair of circuit breakers, each of the circuit breakers being mounted on the joining structure, the pair of circuit breakers and the joining structure being removably disposed in a cassette, the cassette including a base, in which the general nature of the improvement can be stated as including a repositioning apparatus structured to facilitate repositioning of the pair of circuit breakers with respect to the cassette, the repositioning apparatus including a support assembly, the support assembly including a support bar and at least a first guide rail, the at least first guide rail being mounted on the base, the support bar being movable between an inward position and an outward position with respect to the at least first guide rail, the support bar being disposed underneath and supporting the joining structure.